Matlab Recording Program

Update:
The latest version of record.m has been tested on versions 5.3,
6.1, and 6.5 of Matlab on Windows machines. I've also made an attempt at a user manual.

You are welcome to download and use this code for any personal or academic purposes.

The image above contains the time domain waveform and spectrogram of the sentence,
"Shesellsseashells."

The top plot displays a time domain waveform with signal amplitude as a function of
time. The bottom plot shows the signal's spectrogram with frequency on the vertical axis,
and time on the horizontal axis. Blue indicates larger amplitude.

Look at the spectrogram. Note that certain sounds such as "sh"
and "s" (sometimes called unvoiced sounds) contain a
broad range higher frequencies, while other (voiced) sounds, such as "e" or "ell", contain
mostly lower frequencies. Other interesting features seen in the spectrogram are the blue
horizontal bands of energy called formants. Formants are caused by resonance in the vocal
tract, and are considered useful features for speech recognition.